Composition of Y_2O_3-ZrO_2 Amorphous Spheres as Starting Materials of YSZ Ceramics Prepared by Sol-Gel and Ion-Exchange Method

摘要

Y_2O_3-ZrO_2 amorphous spheres were prepared through Sol-Gel and Ion-Exchange method, and yttrium-stabilized zirconia (YSZ) ceramics were prepared using the spheres in order to lower sintering temperature of YSZ ceramics. Na_2O-ZrO_2 amorphous spheres were first synthesized by Sol-Gel and Ion-Exchange method, which allows to exchange between sodium ions and protons of OH groups that formed by hydrolysis of alkoxide, in n-octanol-butanol emulsion. Y_2O_3-ZrO_2 amorphous spheres were then synthesized by the exchange between yttrium and sodium ions of Na_2O-ZrO_2 spheres. Y_2O_3-ZrO_2 spheres at the Y/Zr ratio of 0.0 to 0.2 were obtained by controlling the composition of Na_2O-ZrO_2 spheres and the concentrations of Y(NO_3)_3 during the Y~(3+)/Na~+ ion exchange. YSZ ceramics derived from Y_2O_3-ZrO_2 spheres were crystallized by firing at lower than 500℃, and the sintering at 1450℃ for 5 h resulted in homogeneous and dense YSZ ceramics.